Dip tank and wiper attachment



Oct. 11, 1966 w. s. JONES ETAL 3,277,866

DIP TANK AND WIPER ATTACHMENT Filed Nov. 15, 1965 2 Sheets-Sheet 1 ngz INVENTORS W/LLA/PD 5. JONES EDW/A/ M T/PAMDACK 11, 1966 w. s. JONES ETAL 3,

DIP TANK AND WIPER ATTACHMENT 2 Sheets-Sheet 2 Filed Nov. 15, 1965 INVENTORS WALL/1RD 5- JONES) E DWI/V IV. TPAMDACK United States Patent 3,277,866 DIP TANK AND WIPER ATTACHMENT Willard S. Jones, Indianola, and Edwin N. Tramdack, Va-

lencia, Pa., assignors to Gulf Research & Development Company, Pittsburgh, Pa., a corporation of Delaware Filed Nov. 15, 1965, Ser. No. 507,906 9 Claims. (Cl. 118-100) In a process for the duplication of an original paper copy known as the offset printing process, projection-type offset plates or masters which are papers having an emulsion coating on one side are utilized for producing duplicate prints without an intermediate negative. Immediately prior to the printingroperation these paper masters require wetting or soaking in water or an acid such as acetic acid followed by removal of most of the adhering liquid film. In this wetting operation the masters have conventionally been soaked in completely open flat, shallow horizontal trays. However, shallow horizontal trays are unsatisfactory for this use for many reasons. For example, when utilizing open, horizontal trays spillage and drippage are diflicult to avoid during the removal of the film of excess liquid from the plate after soaking. Also, because these trays have a large open top contamination of the liquid therein by dust is a serious problem. Furthermore, fiat trays require considerable table space which usually is not readily available near theprinting equipment.

In accordance with this invention a vertical soaking tank in combination with a retractable wiper blade is utilized which substantially completely eliminates all the serious problems associated with the horizontal soaking trays. The vertical tank and retractable wiper blade combination of thisinvention eliminates spillage and drippage upon removal of the film of liquid from the master after soaking. Contamination of the liquid with dust is not a serious problem because only a slot-sized surface of liquid is exposed to the atmosphere. The vertical soaking tank of this invention does not require table space but is suited for compact mounting at the side of the printing equipment so that along substantially its entire height the soaking tank is eithenin abuttingengagement with said printing equipment or in very close proximity thereto. The high degree of support imparted to the vertical soaking tank when it is mounted permits it to be operated more advantageously in a mounted position than on a table. On the other hand, it is not advantageous to attach a horizontal soaking tray onto the sideof printing equipment because it cannot be compactly mounted thereat but rather protrudes significantly in a lateral direction from the printing equipment so that operation of a horizontal soaking tray is more advantageous on a table than in a mounted position.

These and other advantages of the invention will be more readily apparent by reference to the accompanying drawings in which FIGURE 1 is an end view of a vertical soaking tank of this invention,

FIGURE 2 is a rear view of the same vertical soaking tank, and

FIGURE 3 is an exploded view of the retractable wiper blade assembly illustrating the operation thereof.

FIGURES 1 and 2 show vertical soaking tank having a liquid reservoir 12 which is narrow in end view, all four sides of which are inclined upwardly and outwardly at the top to provide an enlarged overhead mouth 14. The vertical soaking tank is mounted upon a member 16 of the duplicating machine by means of hanger clips 18 which are attached to the rear of reservoir 12 so that vertical tank 10 is compactly supported against the duplicating machine 'and does not significantly protrude laterally therefrom.

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Reservoir 12 is filled wtih soaking liquor to about the top thereof at level 20 or to a level slightly below the top thereof. The only exposure of liquor in reservoir 12 to the atmosphere is through the narrow elongated slot defining the top of reservoir 12. Master paper sheet 22 is immersed in reservoir 12 with the portion thereof which is to be duplicated fully immersed below liquid level 20. Face 24 of master plate 22 is emulsion coated and requires soaking prior to use in the duplicating machine. FIG- URE 2 shows that the rear of reservoir 12 is about as wide as or only slightly wider than the width of master 22 so that in addition to being a soaking tank reservoir 12 functions as a slot-like receptacle for receiving and securing master 22 against substantial lateral movement. It is shown below that reservoir 12 serves as a centering and aligning means when master 22 is being fed to wiper mechanism 26 upon completion of the soaking operation.

FIGURE 3 presents a detailed view of retractable wiper mechanism 26. The solid lines defining wiper mechanism 26 and master 22 represent the retracted or normal position of the wiper mechanism which is the position of the mechanism When a dry master 22 is being inserted into reservoir 12 with its emulsion surface 24 facing wiper mechanism 26. Wiper mechanism 26 comprises a handle 32 which is pivotally mounted at the center of a fixed transverse rod 34. Spring 36 continually urges the wiper mechanism into a retracted position to permit unobstructed insertion of paper master 22 into reservoir 12.

Upon completion of the soaking operation, master 22 is Withdrawn along the inclined wall 38 of mouth 14 opposite from and facing the inclined wall 28 against which wiper mechanism 26 normally rests. The upper edge of wall 38 is provided with curved surface 39 to prevent injury to wet master 22 upon withdrawal thereof. Upon withdrawal of master 22 handle 32 is utilized to swing wiper mechanism 26 on pivot rod 34 and project it toward inclined wall 38 against the action of spring 36.

Wiper mechanism 26 includes an elongated, pointed rubber squeegee blade 40, such as a windshield wiper' blade, mounted on a rigid holding element 30. Wiper blade 40 is carried by the shank of handle 32 through plunger 42 and bracket 44. Plunger 42 has a transverse bore 43. Pin 45 has a diameter smaller than that of bore 43 and extends through said bore to provide a space therebetween. Leaf spring 46 which is under compression, as indicated by the cutaway portion of wiper mechanism 26 in FIGURE 3, urges the bottom of plunger 42 upwardly to the full extent permitted by the space between pin 45 and the wall of bore 43.

When master 22 is being withdrawn from reservoir 12 after soaking, squeegee 40 is manually projected toward inclined wall 38 and is firmly urged against the emulsion side 24 of the master, as indicated by the dashed lines of FIGURE 3, so that squeegee 40 removes substantially the entire film of fluid on the emulsion surface 24 while flat inclined wall 38 serves to substantially remove the film of water on the opposite surface of the master. The resiliency imparted to squeegee 40 by the clearance between pin 45 and bore 43 and the compressibility of spring 46 permits squeegee 40 to 'exert a uniform pressure along its entire length and avoids excessively tight contact between squeegee 40 and the wet master which could result in tearing while permitting sufliciently close contact to provide a complete wiping action and to overcome any nonuniformity along the sharp outer edge of squeegee 40 which could produce unwiped streaks on the master. A complete wiping action is especially important if an acetic acid soaking solution is employed because introduction of acid into the duplicating machine is highly deleterious.

Squeegee 40 functions while in a stationary position; the master being moved relative to squeegee 40. Remov- Patented Oct. 11, 1966 n a v al ofvvate'rjalong the entire width of master 22 is insured since thelengthof squeegee 40 is greater than the width of master 22, as shown in FIGURE 2. Squeegee 40 is permitted to be wider than the master plate by virtue of the outwardly inclined .walls comprising mouth 14 .of reservoir 12. Because reservoir 12 defines a slot-like opening atlth'e top thereof whose length is about the same as or slightly greater than the corresponding dimension of master 22 and whose width is very small as compared to its length, as is shown in FIGURES l and 2, said slot-like openings serves as means for centering and aligning master 22 relative to squeegee 40, which is preferably longer than both the slot-like opening and the corresponding dimension of master 22, so that each end of'squeegee .40 continually overlaps'its respective side of the master while the master is being withdrawn.

The liquid removed from the master as it travels upwardly past wiper 40 is not squeegeed laterally but is only squeegeed downwardly toward liquid level 20. Mouth 14 of reservoir 12 provides guard means against any possible splashing of liquid draining into the reservoir. However, the slot-like exposure of liquid at level 20 is so small that there is substantially no'occurrence of splashing thereat.

In the apparatus of this invention all the liquid squeegeed from the master is recycled to reservoir 12 for reuse. Not only is there substantially no splashing of liquid at the surface of the reservoir but also the squeegee itself is nonabsorbent and does not retainliquid.

, Various changes and modifications can be 'made without departing from the spirit ofthis invention or the scop thereof as defined in the following claims.

1. An apparatus for treating a projection-type paper master prior to duplication in a printing operation corriprising vertical liquid reservoir tank means defining slot means at the top thereof for receiving said master forv soaking, the length of said-slot meansbeing only slightly greater than the corresponding dimension of said master and the width of said slot means being small in comparison with said length, wall means inclining upwardly and outwardly from said slot means to define an enlarged mouth above said slot means, and retractable squeegee means pivotally secured at oneiof 'said inclined Wall means for projection toward and urging against an opposite inclined wall means.

2. The apparatus of claim 1 including means for mounting said tankmeans in a vertical position.

3. The apparatus of claim 1 wherein said squeegee means is an elongated rubber blade.

4. The apparatus of claim 1 wherein said squeegee means is an elongated rubber blade which is longer than the length of said slot means.

, 5. The apparatus of claim 1 including a curved surface at the upper edge of said opposite Wall means.

6. The apparatus of claim 1 including handle means for projecting said squeegee means toward said opposite wall means. I I

7. The apparatus of claimvl including spring means for resiliently urging said squeegee means against said opposite wall means. I

C 8. The apparatus of claim 1 including spring means for retracting said squeegee means from said opposite wall means.

9."An,apparatus for treating a projection-type paper master prior to duplication in'a printing operation comprising vertical liquid reservoir tank means, means for mounting said tank means in a vertical position, said verti-' cal tank means defining slot means at the top thereof for receiving said master for soaki-ng,the length of said slot meansbeing only slightly greater than the corresponding dimension of said master and the width'of said slot means beingsmall in comparison with' said length, wall means inclining upwardly and outwardly from said slot means to define an enlarged mouth above said slot means, and retractable squeegee means pivotally secured at one of said.

inclined wall means for projection toward and urging against an opposite inclined'wall means, handle means for projecting said squeegeevmeans .toward said opposite wallmeans, said squeegee means comprising elongated rubber blade means which is longer than the length of said slot means, and spring means for resiliently urging said rubber blade means against said opposite wall means.

References Cited by the Examiner UNITED STATES PATENTS 138,767 5/1873 Shepard 1l8100 694,059 2/1902 Harvey 118121 2,645,800 7/1953 'Cahill 15--l00 2,654,109 -10/1953 Barnes l5512 MORRIS KAPLAN, Primary Examiner. 

1. AN APPARATUS FOR TREATING A PROJECTION-TYPE PAPER MASTER PRIOR TO DUPLICATION IN A PRINTING OPERATION COMPRISING VERTICAL LIQUID RESERVOIR TANK MEANS DEFINING SLOT MEANS AT THE TOP THEREOF FOR RECEIVING SAID MASTER FOR SOAKING, THE LENGTH OF SAID SLOT MEANS BEING ONLY SLIGHTLY GREATER THAN THE CORRESPONDING DIMENSION OF SAID MASTER AND THE WIDTH OF SAID SLOT MEANS BEING SMALL IN COMPARISON WITH SAID LENGTH, WALL MEANS INCLINING UPWARDLY AND OUTWARDLY FROM SAID SLOT MEANS TO DEFINE AN ENLARGED MOUTH ABOVE SAID SLOT MEANS, AND RETRACTABLE SQUEEGEE MEANS PIVOTALLY SECURED AT ONE OF SAID INCLINED WALL MEANS FOR PROJECTION TOWARD AND URGING AGINST AN OPPOSITE INCLINED WALL MEANS. 